Tractor power lift with rock-shaft



May 24, 1955 R. D. ACTON Re. 24,006 TRACTOR POIER LIFT IITH ROCK-SHAFTAND SYNCHRONIZED RBIOTE CYLINDER Original Filed Apr11 23, 194B 3Sheds-Sheet 1 fizz/6R2? 13 1/3524 ,2.- Qcfwz,

May 24, 1955 aron; Re. 24,006

TRACTOR PDIER LIFT IITH ROCK-5MP! AND SYNCHRONIZBD REMOTE CYLINDEROriginal. Filed April 23, 1948 3 81:069-821. 2

May 24, 1955 R. n. ACTON Re. 24,006

TRACTOR Pom LIFT wI 'Rocx-smrr AND SYNCHRONIZED REM CYLINDER OriginalFiled April 23. 1948 3 Shuts-Shut 3 United States Patent Oflice Re.24,006 Reissued May 24, 1955 TRACTOR rowan LIFI wmr aocxsrmr'r ANDSYNCHRONIZED REMOTE CYLINDER Russel D. Acton, Chicago, Ill.

Original No. 2,637,259, dated May 5, 1953, Serial No. 22,826, April 23,1948. Application for reissue March 10, 1954, Serial No. 415,458

35 Claims. (Cl. 97-4637) Matter enclosed in heavy brackets If] appearsin the original patent but forms no part of this reissue specification;matter printed in italics indicates the additions made by reissue.

. 2 means. Such devices take various forms such as mechanical linkage,cables, and other structures which must go through the hitch point ofthe implement to be reasonably accurate and whichinvolve complicatedconnecting and disconnecting means. A principal object of the presentinvention is to provide for a tractor connected implement and incombination with the tractor'and implement a preselected indexing typeof power lift structure on the tractor and a simplified powertransmitting means for delivering the same preselective and indexingpower to an adjustable part on an implement.

Another principal object is to provide an hydraulic power cylinderremotely located from a tractor on an implement flexibly connected tothe tractor and to provide through two flexible fluid conducting linesmeans for transmitting selective indexing movement from the tractor tothe hydraulic device on the implement.

Another object is to convert an hydraulic power device on a tractor foroperating a remotely located hydraulic cylinder with selected indexingcontrol. Another specific object is to convert a tractor mountedhydraulic power It is also desirable to provide a control meansaccessible to the operator of the tractor which can be set in anypreselected position determining a preselected position for theimplement. This is particularly desirable for trailbehind implementswhere the operator cannot watch the implement without taking hisattention from the steering and operation of the tractor.

During recent years mechanical and hydraulic power lift systems havebeen developed which operate rock shafts on the tractor for lifting andadjusting implements directly mounted on the tractor. Such systems havebeen very satisfactory as a great many implements can be connected bysimple linkage to a single permanently fixed rock shaft by simple andinexpensive linkage. As a further modification of this system, auxiliaryrock shafts have been spaced on the tractor longitudinally of thebuilt-in power actuated rock shaft thereby providing lifting power fromthe tractor power lift at spaced locations along the tractor. Tofacilitate the operation of such lifting devices means have been workedout as disclosed and claimed in Reissue Patent No. 22,932, by means ofwhich a control readily accessible to the operator can be utilized topreselect a position of the rock shaft by selecting a correspondingposition on a control lever. Such mechanisms have been termed "touchcontrol, "follow: up," preselected," and indexing" types. of controls.Such controls are very significant in the operation of tractor mountedequipment as the steering and anipulation of the other controls on thetractor, such as the clutch, brake, and throttle, require most of theoperator's attention and he is not able to hold a conventional fluidcontrol valve and watch the movement of the implement to determine thedesired operating or lifted position of the implement.

The devices as above set forth have solved the problem of tractormounted tools where they are directly connected to and supported by thetractor in a satisfactory manner. However, there are a great manyimplements flexibly connected to the tractor in trail behind position oralongside the tractor which have supporting means independent of thetractor requiring adjustment to determine the working position of theimplement or a part thereof. Various means have been devised devicehaving a built-in rock shaft to a system in which a remotely locatedhydraulic cylinder can be selectively positioned by the same controlmechanism utilized on the tractor power lift by merely plugging in twofluid conduits leading to the remote cylinder. Another object is toprovide a structure in which a power actuated rock shaft on a tractorand a remotely located power cylinder are controlled in synchronizationwith selected indexing operation by a single valve control mechanism onthe tractor. Another specific object is to provide a tractor mountedpower lift mechanism with power supply means on the tractor with meansfor transmitting synchronized power to a remotely located cylinder andwith valve means to cut out the remotely located cylinder and-continueoperation of the tractor mounted power device.

Another object of the invention is to provide a tractor power devicewith a follow-up indexing mechanism which has a mechanical connectionbetween the control lever and the power output element wherebysynchronization is positively attained at all times, and to provide aremote power cylinder which is synchronized by metering liquid from thetractor cylinder to the remote cylinder,-

said remote cylinder being provided with a valve mechanism by means ofwhich out-of-phase relationship brought about by leakage isautomatically corrected by moving the remote power device to-the ends ofits stroke.

Another object is to provide for a tractor mounted power lift devicehaving two independent power devices with two independent preselectingcontrol levers with a connection to a single remote fluid pressuredevice. said connections being formed to provide for metering fluid fromboth tractor mounted cylinders to the single remote power-lift devicewhereby a single remote cylinder may be utilized with a meteringcapacity equivalent to both of the metering volumes of the two cylinderson the tractor.

The above objects and others which will be apparent from the detaileddescription to follow are accomplished by a construction such as shownin the drawings, in which:

Figure 1 is a side elevation of the rear portion of a tractor with onewheel removed showing an implement flexibly connected to a tractor and apower lift system incorporating a modification of applicants invention.

Figure 2 is a diagrammatic view of the hydraulic system utilized inFigure l, certain corresponding parts such as the rock-shaft and thecontrol lever and linkage having the same reference characters as inFigure l.

Figure 3 shows the same diagrammatic structure as Figure 2 with thecontrol valves in a position to move the rock-shaft in the directionindicated by the arrow and to simultaneously move the piston of theremotely located cylinder in the direction indicated by the arrow.

Figure 4 shows the control valve for cutting out the remote cylinder inthe cut-out position with the remote cylinder being detached therefrom.

Figure 5 shows the same structure of Figure 2 with the control lever ina position to move the rock-shaft in a also secured to the' transverseportion 145 of the draw-bar. Said plow beam as illustrated carries amold-board plow V 151 illustrated as being in working position in thesoil. A

direction opposite to the direction of movement in Figure 4 and to movethepiston in the opposite direction, the direction of movement beingindicated by arrows in Figure 5.

Figure 6 is an enlarged detail showing the rephasing valve operating atone end of the stroke of the remote piston.

Figure 7 shows the piston at the other end of its stroke with therephasing valve in position to open upon further movement of the piston.

In the modification shown in Figures 1 to 7 inclusive, an implement isshown connected to the tractor for simultaneous use of the permanentrock-shaft on the tractor and the flexibly connected remote powerdevice.

Figure 1 shows a tractor having a longitudinally extending body 120,drive axle housings 121, one of which can be seen, and drive axles 122,one of which is shown in section in Figure l. Traction wheels 123, oneof which is removed to better showthe implement and power liftstructure, are carried on the axles 122. A portion of a hood and fueltank structure 124 is shown as well as a steering column 125 and asteering wheel 126. An operators seat 127 mounted on a support 128provides an operators station at the rear of the tractor and adjacentthe steering wheel 126.

A housing 129 mounted at the rear of the tractor forwardly of thesteering wheel 126 contains the power lift valve control structure andreservoir, such parts being shown diagrammatically in Figure 2 alongwith all elements of the hydraulic power system. A supporting structure130 on the housing 129 carries the steering column 126.

A quadrant 131 mounted on the structure 130 provides a support for acontrol lever 132 which is pivotally mounted on the quadrant for arcuatemovement thereacross. A link 133 is pivotally connected to the lever 132and to a vertically extending link 134. Said link 134 is what isordinarily termed a floating link, being pivotally connected by a link135' to a valve member 135 at a midpoint and being pivotally connectedat the end opposite the link 133 to a link 136. Said link, as indicatedin dotted lines, is pivotally connected to an arm 137 carried I formovement with a rock-shaft 138. Said rock-shaft has a lifting arm 139.It will be noted that the rock-shaft is fixed permanently on the tractorby means of an attaching bracket 140.

An expansible hydraulic power device in the form of a cylinder 141 and apiston 142 is shown in dotted lines within the body portion 120 of thetractor, said piston being pivotally connected to the arm 137 wherebysaid piston and cylinder device operates the rock-shaft 138 and thelifting arm 139. As previously stated, the entire power lift mechanism,which is mostly concealed in Figure 1, is shown completely indiagrammatic form in Figure 2.

A reversed or forwardly extending draw-bar 143 is shown as beingpivotally connected by pins 144, one of which is visible in Figure I.Said draw-bar has a translverse forward portion 145 which is shown insection as a 'portion has been removed with the traction wheel at thenear side of the structure to better show the implement and power liftconstruction. A lifting link 146 is pivotally connected at 147 to thelifting arm 139 of the rockshaft and pivotally connected to a bracket.148 mounted on the transverse forward portion of the draw-bar 143. Animplement structure in the form of a plow beam 149 is pivotallyconnected at its forward end to a bracket 150 I pressure device.

gauge wheel 152 for regulating the working depth of the plow 151 isshown ahead of the plow operating on the unbroken soil. Said gauge wheelis carried on a bell crank member 153 pivotally supported intermediateits ends on a bracket 154 secured to the plow beam 149. An upwardlyextending arm 155 of the bell-crank member is pivotally connected to oneend of an expansible fluid Said device has two elements one being acylinder 156 connected to the arm 155 andanother being an element in theform of a piston member 157 pivotally connected to an upstanding bracket158 secured at a rearward location to the plow beam 114. The fluidpressure device is a two-way operating structure having fluid conduitmeans in the form of flexible hoses 159 and 160. Said lines areconnected to the housing 129 and within said housing to other fluidconduits as illustrated in Figure 2.

A longitudinally extending link 161 is pivotally connected at 162 to thepower lift arm 139 and to an upwardly extending arm 163 which is a partof a rockable structure designated in its entirety by the referencecharacter 164 mounted for oscillation on a transverse axis at the rearof the tractor. A bracket 165 is shown as a mounting means for saidrockable structure. Said structure also carries a rearwardly extendingarm 166 to which lifting means in the form of a chain 167 is secured.Said chain is also secured to a bracket 168 fixed to the plow beam 149.

The diagrammatic views of Figures 3 to 7, inclusive, have severalelements corresponding to those described in Figure l and the parts havebeen correspondingly numbered including the valve 135, the piston 142,the cylinder 141, the remote piston 157, and the remote cylinder 156.The fluid lines 159 and 160 also bear the same reference characters aswell as the actuating lever 132, the links 133 and 134, the rock-shaft138, the lifting arm 139, the connecting points 147 and 162, and the arm137 on the rockshaft. So that corresponding parts on the structures canbe readily followed, it will be noted that an additional link 135'appears in the diagrammatic views as connecting the link 134 and thevalve 135. Also an additional link 136 connects the lever arm 137 withthe piston 142 instead of a direct connectionas illustrated in Figure 1.

In Figures 2, 3, and 5 a liquid reservoir 169 is connected by a fluidconduit 170 with a fluid pressure pump 171. Said pump is illustrated asof the meshing gear type being driven by a projecting shaft 172 carryinga gear 173, engagement with a gear 174 forming a part of the power plantof the tractor, for example, the usual gear for driving the cam shaft.It is to be understood that the gear 174 may be driven from any portionof the power plant of the tractor.

A discharge conduit 175 from the pump 171 communicates with a chamber176formed in a valve housing 177. Said chamber communicates throughv abore 178 with a piston chamber 179 in which a piston 180 is mounted forlimited reciprocation. Said piston carries a push rod 181 adapted topass through the bore 178 and constructed to engage a ball valve 182spring-pressed against a seat 183 formed between the bore 178 and thechamber 176.

A by-pass conduit 184 connects the bore 178 with the low pressure fluidsupply conduit 170.

A conduit 185 connects the chamber 179 at the side of the pistonopposite the push rod 181 with the discharge conduit 175 from the pump.A restriction 186 is formed in said conduit to continually bleed fromthe discharge side of the pump a very small volume of liquid when i thepump is operating at high pressure.

A conduit 187 connects the discharge conduit 175 from thepump with acentral point of a control valve housing 188. Said housing together withthe valve 135, which is of the reciprocating piston type forms thefollow-up control valve for the power lift mechanism. The valve 135consists of a piston portion 189, an annular recess portion 190, apiston portion 191, an annular recess portion 192, a piston portion 193,an annularrecess portion 194, and a piston portion 195. The recessportion 190 is put into fluid communication with the recess portion 194by an axially extending conduit 196 formed in the valve body.

A conduit 197 is connected by two branches 198 and 199 with the valvehousing 188 at points spaced laterally a substantial distance atopposite sides of the communication of the supply conduit 187 with thevalve housing 188. A bypass conduit 200 communicating with the reservoir169 communicates through a branch conduit 201 with the valve housing ata point in alinement with the branch conduit 198 and through a branchconduit 202 with the valve housing at a point diametrically in alinementwith the branch conduit 199.

A conduit 203 communicates with the valve housing 188 and with a bore204 formed in a valve housing 205. Said bore communicates with a valvechamber 206, a valve seat 207 being formed around the bore 204 at itsjunction with the chamber 206. A ball valve 208 engageable with saidseat 207 is spring-pressed thereagainst by a compression spring 209. Thebore 207 communicates at its upper end with a piston chamber 210 inwhich a piston 211 is mounted for limited reciprocation. Said pistoncarries a push rod 212 engageable with the ball valve 208 for openingsaid valve upon the movement of the piston in a downward direction.

A conduit 213 communicating with the valve housing 188 as shown inFigure 2 is put into communication by a valve 214 having a passage 215therein with a conduit 216. Said conduit is connectable by a fitting 217with the conduit 160 leading to remote cylinder 156. The conduit 159 isconnected by a fitting 218 with a conduit 219 which as shown in Figure 2is put into communication by a conduit 220 in the valve 214 with aconduit 221. Said conduit communicates with a bore 222 formed in a valvehousing 223. Said bore is joined by a valve seat 224 with a valvecompartment 225. A ball valve 226 urged against the seat 224 by a spring227 normally seals the bore 222. q

At its upper end the bore 222 communicates with a piston chamber 228 inwhich a piston 229 is mounted for limited reciprocation. Said pistoncarries a push rod 230 engageable upon downward movement of the piston229 to unseat the ball valve 226. Above the piston 229 the chamber 228communicates with a conduit 230' which in turn communicates with theconduit 203. A symmetrical conduit 231 communicates with the chamber 210above the piston 211 and with the conduit 213.

Referring particularly to Figures 6 and 7, the remote piston 157 has anenlarged head portion 157' in which a bore 232 is formed. Said bore hasa valve seat 233 at one end of the bore and a valve seat 234 at theother end of the bore. A small diameter outer bore 235 forms acommunication between the seat 233 and one side of the piston head. Asmall bore 236 forms a communication between the valve seat 234 and theother end of the piston head 157'. A valve designated in its entirety bythe reference character 237 is mounted for free reciprocation in thebore 232. Said valve has a central body portion 238 smaller in diameterthan the ,bore 232 and of less length than said bore. A valve seat 239is formed at one end of the central portion 238 and a valve seat 240 isformed at the other end of said central portion. A valve stem 241projects from the valve at one end thereof beyond the valve seat 239through the bore 235. A valve stem 242 formed as an integral part of thevalve projects from the valve seat 240 through the bore 236 at the otherend.

With the valve 135 in the position shown in Figures 2, 3, and 5, theoperation of the device will be explained. In Figure 2 the pistonportion 189 is in a position to close the branch conduits 198 and 201.The piston portion 195 of the valve 135 is in a position to close thebranch conduits 199 and 202. The piston portions 191 and 193 of at theleft end of the piston 142.

when the valve 182 is seated. As previously explained,

the restricted portion 186 of the conduit 185 provides for a continuallimited discharge of fluid, said discharge rate being'obviouslyaccelerated when pressure builds up at the discharge side of the pump inthe conduit 175. As soon as the valve is returned to neutral positionclosing the branch conduits 198 and 199, pressure rapidly builds up inthe conduit 185 by reason of the discharge through the conduit 186. Suchpressure operates the piston moving it to the right unseating the ballvalve 182 and relieving the pump by by-passing fluid dischargedtherefrom through the conduit 184 to the low pressure side of thesystem. Once the ball valve 182 has been opened very little pressure isrequired by the piston 180 to retain it in open position. The resistanceto fluid flow in the lines even with the by-pass open is sufficient tomaintain the piston 180 in the position shown with the ball valve 182 inthe by-pass position illustrated in Figure 2.

It will be understood that with the valve 135 in the position sown inFigure 2 the conduits 203 and 213 are hydraulically locked, therebylocking both the piston 142 and the piston 157 in position againstmovement in either direction.

When it is desired to move the rock-shaft 138 and simultaneously insynchronization therewith the remote piston 157, the control lever 132is manually moved by the operator from his station on the tractor toeither the position shown in Figure 3 or the position shown in Figure 5.Referring first to Figure 3, the operator moves the control lever 132over the quadrant 139 to a preselected indexing position on the quadrantand releases the lever, there being sutficient friction or otherprovision in the detent mechanism of the quadrant to hold the actuatingcontrol lever 132 in any selected position. It is only necessary to havesufiicient holding force to move me valve 135. As the valve iscompletely balanced against any forces exerted by liquid pressure, thereis very little force required to hold the control lever 132 in anyselected position.

With the valve 135 in the position shown in Figure 3 the branch conduits199 and 202 remain closed while the branch conduits 198 and 201 are opento the recess 190. This communication relieves pressure in the conduit197 and likewise in the conduit 185, whereby a valve spring 176' forcesthe ball valve 176 into seated position as shown in Figure 3, the piston180 moving to the left and carrying with it the push rod 181. Pressurethen rapidly builds up in the discharge conduit 175 from the pump and inthe conduit 187. As previously stated, the restriction 186 in theconduitpermits only a very small percentage of the fiuid from the pumpto escape even under high pressure.

It will be noted in Figure 3 that the piston portion 191 of the valve135 has moved to the left to uncover the conduit 203 and to place it incommunication with the conduit 187 through the recess 192. Fluid underpressure is therefore delivered to the bore 204, unseating thespring-pressed valve 208, by-passing the valve and pass ing through ashort conduit 204' into the cylinder 141 In order to more clearlydescribe the operation of the hydraulic system, the chamber at this endof the cylinder 141 has been designated at 141 and the chamber at theother side of the piston through which the rod of the piston passes hasbeen designated at 141".

Pressure being delivered to chamber 141' moves the piston 142 in thedirection of the arrow thereby moving the lifting arm 139 in thedirection of the arrow in a clockwise direction as viewed in Figure 3.

It will be noted that when liquid is delivered under 7 pressure toconduit 203, it is also "delivered with the same pressure to the conduit230', wherebyfluid pres sure is exerted against the piston 229 openingthe ball valve 226 to the position shown in Figure 3. Because of theopening of this valve, fluid from the chamber 141 is delivered outwardlythrough a short conduit 222 through the chamber 225, the bore 222, andthe conduit 221 to the valve 214. With the valve in the position shownin Figure 3, liquid passes through the conduit 220 in the valve to theconduit 219 and therefrom to the conduit 159 leading to the right end ofthe remote cylinder 156. To assist in the description the chamber at thepiston rod side of said cylinder is designated as 156, and the chamberto the other or left-hand end is designated as 156. Fluid beingdelivered to the chamber 156 moves piston 157 to the left as indicatedby the arrow, thereby forcing fluid out through the chamber 156 throughthe conduit 160 through the short conduit 216 through the conduit 215 inthe valve 214 through the conduit 213 to the recess 194. From saidrecess fluid passes through the conduit 196 in the piston through therecess 190 and therefrom out through the branch conduit 201 to theconduit 200 leading back to the reservoir 169.

As the piston 142 moves to the right, the lower end of the link 134 islikewise moved to the right, and as the pivotal connection of the link134 with the link 133 is a fixed fulcrum with any preset position of thecontrol lever, the valve 135 is moved to the right as indicated by thearrow. Movement of the tractor-mounted piston and therock-shaft to whichit is connected and synchronous movement of the remote piston continueuntil the valve 135 returns tothe position shown in Figure 2, in whichposition the valve 182 is opened by functioning of the system aspreviously described and fluid is hydraulically locked in the conduitsleading to the power cylinders. It will be understood that the extent ofmovement of the lifting arm 139 on the tractor rock-shaft and thesynchronous movement of the remote piston will depend entirely upon thepreset positioning of the control lever 132. By means of index marks onthe quadrant 131 or by any other indicating means, the operator knowsthat for any positioning he sets the control lever 132 the rock-shaftand the remote cylinder will move a corresponding distance and beautomatically locked in the new pre-selected or indexed position. As tothe control valve construction 135, it is bilaterally symmetrical asregards the positions to either side of neutral. However, as the remotecylinder is not truly symmetrical as to operation in either direction,Figure 5 shows operation in the other direction with the valve. 135moved to r the right from its neutral position as shown in Figure 2. Theoperation of the pressure build-up device including seating of the valve182 is identical with operation in the other direction, in this case thepiston portion 195 putting the branch conduits 199 and 292 incommunication to cause closing of the by-pass valve 182.

Fluid under pressure is then delivered to the conduit 213 andtherefromthrough the conduit 215 in the valve 214 through the conduit216 and the conduit 160 to the chamber 156, thereby forcing the piston157 to the right in the direction of the arrow. Fluid from the chamber156 is thereby forced out through the conduit 159 through the conduit219 through the conduit 220, the conduit 221, the bore 222, and theshort conduit 222 to the chamber 140 of the tractor-mounted cylinder141. The piston 142 is then moved to the left in the direction of thearrow carrying with it the tractor-mounted rock shaft 138 and thelifting arm 139. Fluid from the chamber 141'- passes out through theshort conduit 204' past the valve 208 which is opened due to pressure inthe conduit 231, through the conduit 203 into the recess 190,

through the conduit 196 into the recess 194, and therefrom through theconduits 202 and 200 back to the reservoir 169. As the piston rod 142and the rock-shaft on 8 the tractor move, motion is transmitted end ofthe link 134 as shown in Figure 5.

The upper end of link 134 being provided with a fixed fulcrum on thelink 133 for any pre-set position of to the lower the control lever 132,movement of the lower end of the link 134 in the direction of the arrowmoves the valve 135 in the same direction as indicated by the arrow tothe left. This action continues with synchronous movement of thetractor-mounted piston 142 and the remote piston 157 until the valve isbrought back .to the neutral position of Figure 2.- A

Referring back to Figure 1, with an explanation of the synchronousfunctioning of the rockshaft 138 with its lifting arm 139 and the remotepiston 157, an explanation can be given of the functioning of the twopoint adjustment structure of Figure 1. With a moldboard plow asillustrated it is essential to adjust the plow with somewhat of aparallel movement. If only the gauge wheel 153 were relied upon the plowwould not be in proper plowing position and would tend to run in or outdepending upon the tilt with respect to its position of proper balancedrelationship with respect to the ground surface. It is thereforedesirable to adjust the hitch point of the plow beam 149 simultaneouslywith the adjustment of the gauge wheel 152. This is accomplished with apower lift system as illustrated by connecting the forward hitch pointof the plow with the swinging draw-bar 143 through the link 146 with thepower lift arm 139. At the same time the synchronized remote cylinderpower lift unit is connected between the adjusting arm for the gaugewheel 152 and the bracket 158 on the plow beam. By proper proportioningof the lever arms on the bell-crank member 153 the proper synchronizedadjustment is obtained between the hitch point of the plow beam 149 onthe swinging drawbar and the relative position of the gauge wheel. Thisis a very significant achievement in obtaining the proper adjustment ofa tractor-connected implement having its own gauge means, whilepermitting the desired flexibility between the tractor and theimplement.

As a further structural organization, the additional link 161 asconnected from the lifting arm 139 through the bell-crank member 164 andthe chain 167 with the plow beam 149, provides means for lifting theentire implement structure free from the ground after the lifting arm139 has moved in an anti-clockwise direction a sufiicient distance totake up the slack in the chain 167. The

cylinder minus the cross sectional area of the piston rod times thelength of the piston stroke. Referring to the remote cylinder 156, itwill be noted that the bore of the cylinder is substantially larger thanthe bore of the cylinder 141 and that the stroke is also substantiallylonger. More significant is the fact that the cross section of thepiston rod 157 is several times that of the piston rod 142. By thisconstruction the displacement capacity or volumetric displacement of thechamber 156" at the piston side of the remote cylinder 156 which is thecross sectional area of the bore of the cylinder minus the crosssectional area of the piston rod 157 times the length of stroke, is madethe same as the volumetric displacement of the chamber 141 at the pistonrod side of the cylinder 141. Said chambers 141" and 156 with theconduits 159, 219, 220, and 222' form a closed secondary circuit throughwhich the same confined liquid passes one end of its stroke while theother is at the reverse end of its stroke, fluid displaced from one ofsaid chambers completely fills the other chamber and assures a completestroke. By thusly providing a closed secondary metering system withchambers of equal displacement capacity in the tractor mounted meteringcylinder and the remote indexing cylinder, any desired variation may beprovided in the, bore and stroke of the remote cylinder and a number ofdetachable cylinders or difierent bore and stroke charhcteristics may beprovided and interchangeably utilized. As illustrated, altho the drawingis not to exact scale, the remote cylinder 156 has over twice thedisplacement capacity as the chamber 141 while the chambers 141 and 156are constructed to have the same displacement capacity. This showingillustrates but one embodiment of the possibilities of wide vari ationin bore and stroke while retaining equal displacement capacities at themetering side of the pistons which form elements of the closed secondarycircuit of system.

In the operation of a device as described, it is obvious that after along length of time or after excessive wear of piston and cylinder partsor packing, there will be some leakage between one side of the pistonand the other, that is, between the chambers 141 and 141' and out of thechamber 141 around the piston rod. Also the same thing will occurbetween the chambers 156 and 156 of the cylinder 157. As for thecylinder 141, leakage past the piston and out of the chamber 141 is notof great significance as the follow-up linkage is mechanically connectedto the piston 142 and does not returm the valve to neutral positionuntil the piston 142 has moved an amount determined by the indexingposition of the control lever 132. However, as leakage occurs betweenopposite sides of the piston 157 or the piston 142 there will be more orless fluid in the closed secondary Figure 4 illustrates in a simplifieddiagram the same structure as Figures 2, 3, and 5 in which the valve 214is turned 90 to a position putting the conduit 213 into directcommunication with the conduit 221. With this position of the valve, theconduit 216 is put into direct,

communication with the conduit 219 by means of the conduit 220 in thevalve. It will be understood that this valve may be thrown out any timeby the operator, such valve being illustrated in Figure l, at whichpoint furcircuit between the chambers 141" and 156". Assuming thatliquid has leaked out of said closed secondary circuit, referring to thedirection of operation shown in Figure 3. there will not be sufiicientliquid to move the piston 157 to the full extent of its stroke in thedirection shown in Figure 3. Suppose, however, that there is too smallan amount of fluid in the secondary circuit, and the operation reversedas shown in Figure 5. In this direction of operation the piston 157would reach the end of its stroke before suflicient liquid had beendischarged from the secondary circuit to return the piston 142 to thefull extent of its stroke. In this case a condition would be reached asshown in Figure 6 where the rephasing valve comes into action. As thepiston 157 reaches the ends of its stroke and with fluid still beingdelivered to the chamber 156, the valve stem 242 abuts the end of thecylinder 156 unseating the valve 237 which had here tofore been seatedby pressure in the chamber 156' with the seat 240 in sealingrelationship with respect to the seat 234. This mechanically opens thevalve 237 and permits fluid being delivered to chamber 156' to passthrough the bore 235, the bore 238, and the bore 236 into the chamber156 and therefrom back to the chamopened in the opposite direction topermit fluid toby-pass from the chamber 156 to the chamber 156 until thepiston 142 is brought to its end position resulting in synchronizing thetwo cylinders for subsequent operation. It is therefore evident that thesystem is self-synchronizing merely by moving the control lever to thefull length of its travel in either position. This is a particularlyther movement of the synchronized remote cylinder is stopped andwhereafter the operator may use only the tractor-mounted rock shaft.This is particularly important as fun great many operations it is notnecessary to have a flexibly connected remote cylinder. By disconnectingthe fittings 217 and 218, the remote cylinder may be removed with theimplement or separated therefrom and not used until need has arisen.Also the cylinder may be left on the implement or mounted on the tractoras shown by dotted lines in Figure 1 or disconnected so that it does notoperate during the use of the rockshaft. When the remote cylinder 156 isagain connected through thefittings 217 and 218 for functionaloperation, it is obvious that the touch control lever 132 may be in anyone of its indexed positions with the tractor-mounted cylinder 142 inany one of its positions. With a rephasing device as described, it isimmaterial where either the piston 142 orthe piston 157 is with respectto its cylinder when. the attachment is made as said cylinders may bebrought into synchronization at once merely by moving the lever 132vinto each of its end positions and allowing the valve 135 to be carriedback to its neutral position by operation of the rock-shaft 139. Theremote cylinder is then in synchronized relationship for operation withthe rock-shaft or for operation without the rockshaft, it being possibleto obtain indexing or preselected positioning'of the remote cylinder bythe metering means provided by the tractor-mounted mechanism.

By a structure as disclosed and explained, applicant has obtainedselecting indexing control for a tractormounted rock-shaft and has atthe same time obtained the same selective indexing control of a flexiblyconnected remote cylinder for implements flexibly connected to thetractor without the use of any additional mechanism.

Means have also been provided for synchronizing the two cylinders andfor bringing the remote cylinder into synchronized follow-uprelationship with respect to the control lever.

It is understood that applicant claims as his invention allmodifications falling within the scope of the appended claims What isclaimed is:

l. A hydraulic power attachment for tractors comprising a pump adaptedto be driven from the power plant of the tractor, a-two-way actingcylinder and piston device adapted to be connected to the tractor, valvemeans for supplying fluid under pressure from said pump to said cylinderat one side of said piston, means connected to said piston for supplyingmechanical power for a mechanism mounted on the tractor, a flexibleconduit removably connected to said cylinder at the other side of saidpiston, a second remotely located cylinder and piston device, saidconduit being connected to said second cylinder whereby said secondcylinder is flexibly mounted, and means selectively operable to providea fluid communication direct from said other side of said first namedpiston to the valve means whereby the tractor mounted cylinder andpiston device is operable independently of the remote cylinder'andpiston device.

2. A device as set forth in claim 1 in which a rockshaft is adapted forbeing mounted on the tractor and in which the first mentioned cylinderand piston device cylinder at one side of said piston, a flexibleconduit connected to said cylinder at the other side of said piston, animplement adapted to be flexibly connected to the tractor and having anadjustableelement thereon, and a second cylinder and piston devicemounted on said implement and connected to the adjustable element.thereon, said conduit being connected to said second cylinder and meansto provide fluid communication between the conduit and the valve meanswhereby the' tractor mounted cylinder and piston device is operableindependently of the second named cylinder and piston device.

4. A hydraulic power attachment for tractors comprising a pump adaptedto be driven from the power plant of the tractor, a rock-shaft adaptedto be on the tractor, a two-way acting cylinder and piston deviceconnected to said rock-shaft, valve means for supplying fluid underpressure in metered amounts from said pump to said cylinder at one sideof said piston, a flexible conduit connected to said cylinder at theother side of said piston, an implement flexibly connected to thetractor and having an adjustable element thereon and a second remotelylocated cylinder and piston device adapted to be mounted on saidimplement and connected to the adjustable element thereof, said conduitbeing connected to said second cylinder.

5. A hydraulic power attachment for tractors comprising in combinationwith a tractor a pump adapted to be driven from the power plant of thetractor, a cylinder and piston device mounted on the tractor, a fluidreservoir and associated valve means mounted on the tractor, fluidconducting means connecting the pump, reservoir and valve means, aconduit means connecting said valve means and one end of the cylinder toprovide for flow of fluid under pressure to the cylinder and for returnflow from the cylinder, manual control means for said valve means,mechanically actuated follow-up 1 means including motion transmittingmeans connected to move with said piston and connected to the controlmeans for' the valve means, said valve means and con-. trol means andthe motion transmitting means being so constructed and arranged that anyposition of the piston is preselectable by said control means therebyproviding an indexing control of the piston, a second remotely locatedtwo-way acting cylinder and piston device adapted to be mounted on animplement flexibly connected to the tractor, a movable element on saidimplement, said piston and cylinder device being connected to said ele*ment for adjusting the same, a flexible second conduit means connectedto the other end of the first named cylinder and to one end of saidsecond cylinder and a third conduit means connected to the other end ofsaid second named cylinder and to the valve means, said valve meanshaving'a neutral position and being arranged and constructed whenmanually shifted to one position in one direction from said position todeliver fluid under pressure from the pump to the one end of thecylinder on the tractor and to another position in the oppositedirection from said neutral position to supply fluid under pressure tothe other end of the cylinder on the implement, whereby the second namedpiston follows in syn- I chronization the movements of the first namedpiston and whereby an indexing control is provided from the tractor forthe remote cylinder preselectably to any predetermined positionthroughout its range of movement by the manual control means on thetractor.

6. A hydraulic power attachment for tractors comprising in combinationwith a tractor a'pump adapted to be driven from the power plant of thetractor, an implement actuating rock-shaft mounted on the tractor,

rated follow-up means including motion transmitting means connected tomove with said piston and connected to the control-means for the valvemeans, said valve means and control meansand the motion transmittingmeans being so constructed and arranged that any position of the pistonis preselectable by said control means thereby providing an indexingcontrol of the piston, a second remotely located two-way acting cylinderand piston device adapted to be mounted on an implement flexiblyconnected to the tractor, a movable element on said implement, saidpistonand cylinder device being connected to said element for adjustingthe same, a flexible second conduit means connected to the other end ofthe first named cylinder and to one end of said second cylinder and athird conduit means connected to the other end of said second namedcylinder and to the valve means, said valve means having a neutralposition and being arranged and constructed when manually shifted to oneposition in one direction from said position to deliver fluid underpressure from the tractor and to another position in the oppositedirection from said neutral position to supply fluid under pressure tothe other end of the 'cylinder on the implement, whereby the secondnamed piston follows in synchronization the movements of the first namedpiston and the rock-shaft on the tractor and whereby an indexing controlis provided from the tractor for the rock-shaft and the remote cylinderpreselectably to any predetermined position throughout its range ofmovement by the manual control means on the tractor;

7. A device as set forth in claim 5 in which the piston of the remotelylocated device is provided with valve structure operable to stop fluidflow to the piston by fluid pressure at either side thereof andincluding means projecting between the opposite sides of the piston andthe ends of a cylinder to mechanically open said valve structure forflow of fluid through the piston when said piston reaches the endof itsstroke in either direction prior to the piston of the tractor mounteddevice reaching the end of its structure in the corresponding direction.

8. A device as set forth in claim 5 in which the piston of the remotelylocated device is provided with a bore therethrough having an enlargedcentral portion and in which a valve member has a body portion in saidcentral portion of the bore and is formed to abut adjacent therestricted portions at either end of said central portion to form avalve seat, said valve structure being further formed with stems at eachend extending beyond both sides of the piston whereby said valvestructure is seated by fluid pressure at either side of the piston andis mechanically opened by contact of said stems with the cylinder whenthe piston of the remote device reaches the end of its structure beforethe piston of the tractor mounted device reaches the end of itsstructure in the corresponding movement;

9. A hydraulic power attachment for tractors comprising in combinationwith a tractor a pump adapted to be driven from the power plant'of thetractor, an implement actuating rock-shaft mounted on the tractor, a

- cylinder and piston device mounted on the tractor and return flow fromthe cylinder, manual control means for said valve means, mechanicallyactuated follow-up means including motion transmitting means connectedto move with said piston and connected to the control means for thevalve means, said valve means andcontrol means and themotion'transmitting means being so constructed and arranged that anyposition of the piston is preselectable by said control means therebyproviding an indexing conv trol of the piston, a second remotely locatedtwo-way acting cylinder and piston device adapted to be mounted on animplement flexibly connected to the tractor for adjusting an elementthereof, a flexible second conduit means connected to the other end ofthe first named cylinder and to one end of said second cylinder and athird conduit means connected to the other endof said second namedcylinder and to the valve means, said valve means having a neutralposition and being arranged and constructed when manually shifted to oneposition in one direction from said position to deliver fluid underpressure from the pump to the one end of the cylinder on the tractor andto another position in the opposite direction from said neutral positionto supply fluid under pressure to the other end of the cylinder on theimplement, whereby the second named piston follows in synchronizationthe movements of the first named piston and the rockshaft on the tractorand whereby an indexing control is provided from the tractor for therock-shaft and the remote cylinder preselectably to any predeterminedposition throughout its range of movement by themanual control means onthe tractor.

der, connected by said conduits and adapted to be located on animplementflexibly connected to the tractor and connected to an implement part foradjustment thereof, said valve means being operable to supply fluiddirect to the first mentioned cylinder with the conduits to the remotecylinder being blocked out of communication, said valve means being alsoconstructed to be shifted to supply fluid direct from the valve means toone of said conduits and to supply fluid from the other conduit to thetractor-mounted cylinder.

12. In a tractor havinga power plant and a fluid pump driven thereby andin combination therewith a hydraulic power attachment comprising atwo-way acting cylinder and piston device mounted on the tractor, arock-shaft on the tractor, the piston of said device being operativelyconnected to the rock-shaft for oscillating said rock-shaft in either oftwo directions, a lifting arm on said rockshaft for connectingimplements thereto, valve structure including a valve movable in twodirections from a neutral position, means for supplying fluid underpressure from said pump to said valve structure, means for supplyingfluid from said valve structure to one and of said 10. In a tractorhaving a power plant and a fluid pump 7 driven thereby and incombination therewith a hydraulic power attachment comprising a two-wayacting cylinder and piston device mounted on the tractor, a rock-shafton the tractor, the piston of said device being operatively connected tothe rock-shaft for oscillating said rock-shaft in either of twodirections, a lifting arm on said rockshaft, an implement connected tosaid rock-shaft for vertical adjustment thereby, valve structureincluding a valve movable in two directions from a neutral position,means for supplying fluid under pressure from said pump to said valvestructure, means for supplying fluid from said valve structure to oneend of said cylinder, conduit means for supplying fluid from said valveto the other end of said cylinder, a valve means interposed in saidconduit means, two conduits connected to said valve means, a cylinderand piston device, the cylinder of said device being connected to saidconduits and being located on said implement, said implement having apart to be adjusted and said cylinder and piston device being connectedto said implement part for adjustment thereof, said valve means beingoperable to supply fluid direct to the first mentioned cylinder with theconduits to the remote cylinder being blocked out of communication, saidvalve means being also constructed to be shifted to supply fluid directfrom the valve means to one of said conduits and to supply fluid fromthe other conduit to the tractor-mounted cylinder.

11. For a tractor having a power plant, a pump adapted to be driven fromthe power plant of the tractor and in combination therewith, a two-wayacting cylinder and piston device mounted on the tractor, a rock-shafton the tractor, the piston of said device being operatively connected tothe rock-shaft for oscillating said rock-shaft in either of twodirections, a lifting arm on said rock-- shaft for connecting implementsthereto; valve structure including a valve movable in two directionsfrom a neutral position, means for supplying fluid under pressure fromsaid pump to said valve structure, means for supplying fluid from saidvalve structure to one end of the cylinder of said cylinder and pistondevice conduitmeans for supplying fluid from said valve to the other endof said cylinder, and in combination a valve means inter posed in saidconduit means on the tractor, two conduits connected to said valvemeans, a remotely located cylincylinder, conduit means for supplyingfluid from said valve to the other end of said cylinder, a valve meansinterposed in said conduit means, two conduits connected to said valvemeans, a remotely located cylinder and piston device, the cylinder ofsaid cylinder and piston device being connected to said conduits andadapted to be located on an implement flexibly connected to the tractorand connected to an implement part for adjustment thereof, said valvemeans being operable to supply fluid direct to thefirst mentionedcylinder with the'conduits to the remote cylinder being blocked out ofcommunication, said valve means being also constructed to be shifted tosupply fluid direct from the valve means to one of said conduits and tosupply fluid from the other conduit to the tractor-mounted cylinder.

13. A hydraulic power attachment for tractors having a power plantcomprising: a pump adapted to be driven from the power plant of thetractor, a two-way acting cylinder and piston device adapted to bemounted on the tractor, a rock-shaft adapted to be mounted on thetractor, the piston of said device being operatively connected to therock-shaft for oscillating said rock-shaft in either of two directions,a lifting arm on said rock-shaft for connecting implements thereto,valve structure including a valve movable in two directions from aneutral position, means for supplying fluid under pressure from saidpump to said valve structure, means for supplying fluid from said valvestructure to one end of said cylinder, conduit means for supplying fluidfrom said valve to the other end of said cylinder, valve meansinterposed in said conduit means, two conduits connected to said valvemeans, a remotely located piston and cylinder connected by saidconduits, one of said conduits being connected to each end of thecylinder, said remotely located piston and cylinder device being adaptedto be located on an implement flexibly connected to the-tractor andconnected to an implement part for adjustment thereof, said valve meansbeing operable to supply fluid direct to the first mentioned cylinderwith the conduits to the cylinder which is remotely located beingblocked out of communication, said valve means being also constructed tobe shifted to supply fluid direct from the valve means to one of saidconduits and to supply fluid from the other conduit to thetractor-mounted cylinder.

14. A tractor-mounted implement and a lifting and adjusting devicetherefor comprising in combination with a tractor having a pump adaptedto be driven from the power plant thereof, an implement actuatingrock-shaft mounted on the tractor, a soil working implement having aframe structure, a lifting connection between the rockshaft and theforward end of said structure, a cylinder mounted'on the tractor, apiston reciprocable in said cylinder and connected to said rock-shaftfor oscillation thereof, a fluid reservoir and associated valve meansmounted on the tractor, fluid connections between the pump, thereservoir and the valve means, a conduit connecting said valve means andone end of the cylinder to provide for flow of fluid under pressure tothe cylinder and for return flow from the cylinder, manual control meansfor said valve means, mechanically operated valve actuating meansincluding motion transmitting means connected to move with the pistonand the rock-shaft andconnected to the manual contrdl means means havinga neutral position and being arranged and constructed when manuallyshifted to one position in one direction from said neutral position todeliver fluid under pressure from the pump to said one end of thecylinder,

and to another position in the opposite direction from said for thevalve means, said valve nection with therock-shaft, a pistonreciprocable in said neutral position to drain fluid from said end ofthe piston back to the reservoir, a second cylinder located on theimplement structure, said implement structure having an adjustablewheeled support connected thereto at apoint spaced from the liftingconnection with the rock-shaft, a piston reciprocable in said secondcylinder and connected to said support for thereby the working depth ofthe implement, a second conduit means connected to the other end of thefirst named cylinder and to one end of said second cylinder, and a thirdconduit means connected to the other end of the second named cylinderand to the valve means, said valve means being so arranged andconstructed that when fluid is being delivered under pressure to the oneend of the cylinder on the tractor fluid is drained from the other endfrom the other end of the cylinder on the tractor fluid is suppliedunder pressure to the one end of the cylinder on adjusting the positionthereof and. i

of the cylinder on the implement and when fluid is drained 7 l theimplement, whereby the second named piston follows in synchronizationthe movement of the first named piston and its associated rock-shaft onthe tractor, and whereby an indexing control is provided from thetractor for synchronous operation of the rock-shaft, and the wheeledsupport on the implement preselectable to any predeterminedpositionthrough their ranges of movement by the manual control means on thetractor and whereby the implement frame structure is moved bodily in agenerally vertical direction with a movement of translation.

15. A tractor-mounted implement and a lifting and adjusting devicetherefor comprising in combination with a tractor having a pump adaptedto bedriven from the power plant thereof, an implement actuatingrock-shaft mounted on the tractor, a vertically movable liftingstructure at the rear of the tractor, linkage connecting said structureand said rock-shaft for simultaneous movement thereof, a soil workingimplement having'a frame struc-- ture, a lifting connection between therock-shaft and the forward end of said structure, a flexible liftingconnection between-the lifting structure at the rear of the tractor andsaid implement structure, a cylinder mounted on the tractor, a pistonreciprocable in said cylinder and connected to said rock-shaft foroscillation thereof, a fluid reservoir and associated valve meansmounted on the tractor, fluid connections between the pump, thereservoir and the valve means, a conduit connecting said valve means andone end, of the cylinder to provide for flow of fluid underpressure tothe cylinder and for return flow from the cylinder, mani ual controlmeans for said valve means, mechanically'operated valve actuating meansincluding motion transmitting means connected to move with the pistonand the rock-shaft and connected to the manual control means for thevalve means, said valve means having a neutral position and beingarranged andconstructed when manually shifted to one position in onedirection implement structure having an adjustable wheeled supportsecond cylinder and connected to said support for adjusting the positionthereofand thereby the working depth of the implement; a second conduitmeans connected to the other end of the first named cylinder and to oneend of said second cylinder, and a third conduit means connected to theother end of the second named cylinder and to the valve means, saidvalve means being so arranged and constructed that when fluid is beingdelivered under pressure to the one end of the cylinder on the tractorfluid is drained from the other end of the cylinder on the im- 1 plementand when fluid is drained from the other end of the cylinder on thetractor fluid is supplied under pressure to the one end of the cylinderon the implement, whereby the second named piston follows insynchronization the movement of the first named piston and itsassociated rock-shaft on the tractor, and whereby an indexing control isprovided from the tractor for synchronous operation of the rock-shaft,the lifting structure at the rear of the tractor, and the wheeledsupport on the implement preselectable to any predetermined positionthrough their ranges of movement by the manual control means on thetractor, said lifting connection from the lifting structure at the rearof the. tractor and the wheeled support on the implement having asubstantial lost motion whereby the wheeled support is eflectivethroughout a substantial range of movement of the lifting mechanism todetermine the working depth of the implement and whereby the other rangeof movement of the lifting mechanism the implement is lifted completelyfrom the ground with a substantially parallel movement. I 1

16. A tractor-mounted implement and a lifting and adjusting devicetherefor comprising in combination with a tractor having a pump adaptedto be driven from the power plant thereof, an implement actuatingrock-shaft mounted on the tractor centrally thereof, a soil workingimplement having a frame structure lying beneath the tractor, a liftingconnection between the rock-shaft and the forward end of said structure,a cylinder mounted on the tractor, a piston reciprocable in saidcylinder and connected to said rock-shaft for oscillation thereof, afluid 'reservoir and associated valve means mounted on the tractor,fluid connections between the pump, the reservoir and the valve means, aconduit connecting said valve means and one end of the cylinder toprovide for flow of fluid under pressure to the cylinder and for returnflow from the cylinder, manual control means for said valve means,

mechanically operated valve actuating means including motiontransmitting means connected to move with the piston and the rock-shaftand connected to the manual control means for the valve means, saidvalve means having a neutral position and being arranged and constructedwhen manually shifted to one position in one direction from said neutralposition to deliver fluid under pressure from the from said neutralposition to deliver fluid under pressure from the pump to said one endof the cylinder, and to another position in the opposite direction fromsaid neutral position to drain fluid from said end of the piston back tothe reservoir, a second cylinder located on the implementstructure,-said implement structure having an adjustable wheeled supportconnected thereto at a point spaced from the." lifting connection withthe rock-shaft, a piston reciprocable in said second cylinder andconnected to said support for adjusting the position thereof and therebythe working depth of the implement, a second conduit means connected tothe other end of the first named cylinder and to one end of said secondcylinder, and a third conduit means connected to the other end of thesecond named cylinder and to the valve means, said valve means being soarranged and constructed that when fluid is being delivered underpressure to the one end of the cylinder on the tractor fluid is drainedfrom the other end of the cylinder on the implement and when fluid isdrained from 17 plement, whereby the second named piston follows insynchronization themovement of the. first named piston and itsassociated rock-shaft on the tractor, and whereby an indexing control isprovided from the tractor for synchronous operation of the rock-shaft,and the wheeled support on the implement preselectable to anypredetermined position through their ranges of movement by the manualcontrol means on the tractor and whereby the implement frame structureis moved bodily in a generally vertical direction with a movement oftranslation.

17. A tractor mounted implement and a lifting and adjusting devicetherefor comprising in combination with a tractor having a pump adaptedto be driven from the power plant thereof, an implement actuating rockshaft mounted on the-tractor centrally thereof, a vertically movablelifting structure at the rear of the tractor, linkage connecting saidstructure ancl said rock-shaft for simultaneous movement thereof, a soilworking implement having a frame structure lying beneath the tractor, alifting connection between the rock-shaft and the forward end of saidstructure, a flexible lifting connection between the lifting structureat the rear of the tractor and said implement structure, a cylindermounted on the tractor, a piston reciprocable in said cylinder andconnected to said rock-shaft for oscillation thereof, a fluid reservoirand associated valve means mounted on the tractor, fluid connectionsbetween the pump, the reservoir and the valve means, a conduitconnecting said valve means and one end of the cylinder to provide forflow of fluid under pressure to the cylinder and for return flow fromthe cylinder, manual control means for said valve means, mechanicallyoperated valve actuating means including motion transmitting meansconnected to move with the piston and the rock-shaft and connected tothe manual control means for the valve means, said valve means having aneutral position and being arranged and constructed when manuallyshifted to one position in one direction from said neutral position todeliver fluid under pressure from the pump to said one end of thecylinder, and to another position in the opposite direction from saidneutral position to drain fluid from said end of the piston back to thereservoir, a second cylinder located on the implement structure, saidimplement frame structure having an adjustable frame wheeled supportconnected thereto at a point spaced from the lifting connection with therock-shaft, a piston reciprocable in said second cylinder and connectedto said support for adjusting the position thereof and thereby theworking depth of the implement, a second conduit means connected to theother end of the, first named cylinder and to one end of said secondcylinder, and a third conduit means connected to the other end of thesecond named cylinder and to the valve means, said valve means being soarranged and constructed that when fluid is being delivered underpressure to the one end of the cylinder on the tractor fluid is drainedfrom the other end of the cylinder on the implement and when fluid isdrained from the other end of the cylinder on the tractor fluid issupplied under pressure to the one end of the cylinder on the implement,whereby the second named piston follows in synchronization the movementof the first named piston and its associated rock-shaft on the tractor,and whereby an indexing control is provided from the tractor forsynchronous operation of the rock shaft, the lifting structure at therear of the tractor, and the wheeled support on the implementpreselectable to any predetermined position through their ranges ofmovement by the manual control means on the tractor, said liftingconnection from the lifting structure at the rear of the tractor. andthe wheeled support on the implement having a substantial lost motionwhereby the wheeled support is effective throughout a substantial rangeof movement of the lifting mechanism to determine the working depth ofthe implement and whereby the other range of movement of the liftingmechanism the implement is lifted completely from the ground with asubstantially parallel movementa inder and in which valve means areprovided for open-- ing said passage for the flow of fluid in eitherdirection,

said valve means including an element projecting from each side of thepiston and engageable with the cylinder when the piston reaches the endof its stroke.

19. A device as set forth in claim 17 in which the piston of theremotely located device is provided with valve structure operable tostop fluid flow to the piston by fluid pressure at either side thereofand including means projecting between the opposite sides of the pistonand the ends of a cylinder to mechanically open said valve structure forflow of fluid through the piston when said piston reaches the end of itsstroke in either direction prior to the piston of the tractor mounteddevice reaching the end of its movement in the corresponding direction.

20. A device as set forth in claim 17 in which the piston of theremotely located device is provided with a bore therethrough having anenlarged central portion and in which a valve member has a body portionin said central portion of the bore and is formed to abut adjacent therestrictedportions at either end of said central portion to form a valveseat, said valve structure being further formed with stems at each endextending beyond both sides of the piston whereby said valve structureis seated by fluid pressure at either side of the piston and ismechanically opened by contact of said stems with the cylinder when thepiston of the remote device reaches the end of its stroke before thepiston of the tractor mounted device reaches the end of its stroke inthe corresponding movement.

21. A hydraulic power attachment for tractors comprising in combinationa pump adapted to be driven from the power plant of the tractor, acylinder and piston device mounted on the tractor, a fluid reservoir andassociated valve means mounted on the tractor, fluid conducting meansconnecting the pump, reservoir and valve means, a conduit meansconnecting said valve means and one end of the cylinder to provide forflow of fluid under pressure to the cylinder and for return flow fromthe cylinder, manual control means for said valve means, a secondremotely located two-way acting cylinder and piston device, a conduitconnected to one end of said second cylinder and adapted to be put intocommunication with the other end of the first named cylinder, theconnected ends of said. cylinders having the same displacement capacity,the working phase relationship being such that one cylinder at, saidconnected ends is full at that end when the other cylinder is empty atsaid connected end, a conduit connected to the other end of the secondcylinder and adapted to be put into communication with the valve means,and means for removing said second cylinder from operation includingmeans for conducting fluid from the tier directly to the valve meansindependent of the second named cylinder.

22. A device as set forth in claim 21 in which said second namedcylinder is provided with synchronizing means including valve meansautomatically opened at the end of the piston stroke in either directionwhereby said cylinder can be connected to the first named cylinder foroperation therewith in any phase relationship and is thereafter broughtinto synchronized phase relationship by operating the first named pistonto its extreme position in both directions.

23. A hydraulic poweratta'chment for" tractors comprising in combinationa pump adapted to be driven from the power plant of the tractor, animplement actuating rock-shaft mounted on the tractor, a cylinder andpiston device mounted on the tractor and connected to said rockshaft foroscillation thereof, a fluid reservoir and associated valve meansmounted on the tractor, fluidconducting means connecting the pump,reservoir other end of the first named cylinmeans connected to move withsaid piston operable to i return the valve means to neutral position andthereby stop movement of the piston when the piston has reached apredetermined position, a second remotely located two-way actingcylinder and piston device, a conduit connected to one end of saidsecond cylinder and adapted to be put into communication with the otherend of the first named cylinder, the connected ends of said cylindershaving the same displacement capacity whereby the contents of onecylinder at said connected ends upon a complete discharge stroke thereofcompletely fills the other cylinder at its connected end and completes astroke thereof in the reverse direction, a conduit connected to theother end of said second cylinder and adapted to be put intocommunication with the valve means, said valve means having a neutralposition in which fluid is locked in said conduits and said cylindersand being arranged and constructed when manually shifted to one positionto deliver fluid under pressure to one end of the first named cylinderand when shifted in the opposite direction to deliver fluid underpressure to the other end of the second named cylinder, and meansproviding for removing the second cylinder from operation includingmeans for conducting fluid from the other end of the first cylinderdirectly to the valve means.

24. A device as set forth in claim 23 in which said second namedcylinder is provided with synchronizing means including means to bypassfluid flow around the piston at the extreme end of the movement of thepiston in either direction of movement.

25. A hydraulic power attachment for tractors having a power plantcomprising a pump attached to be driven from the power plant, a two-wayacting cylinder and piston device adapted to be mounted on the tractor,valve means, fluid conducting means connecting said pump and said valvemeans, a conduit connecting said valve means and one end of the cylinderto provide for flow of fluid under pressure to the cylinder, at secondremotely located cylinder and piston device, a second conduit connectedto the other end of said first named cylinder and to one end of saidsecond named cylinder, a third conduit connected to the other end ofsaid second named cylinder and to the valve means, and means to cut offcommunication of the second and third conduits with the second namedcylinder and to provide a communication directly between the secondconduit and the third conduit whereby the tractor mounted cylinder andpiston device is operable independently of the remotely located cylinderand piston device.

26. A hydraulic power attachment for tractors having a power plantcomprising a pump attached to be driven from the power plant of thetractor, a two-way 20 acting cylinder and piston device adapted to bemounted on the tractor, valve means, fluid conducting means connectingsaid pump and said valve means, a conduit connevting said valve meansand one end of the cylinder to provide for flow of fluid under pressureto the cylinder and for drainage from the cylinder, a second remotelylocated two-way acting cylinder and piston device, a second conduitconnected to the other end of the first named cylinder and to one end ofthe second named acting cylinder and piston device adapted to be mountedon the tractor, valve means, fluid conducting means connecting said pumpand said valve means, a conduit connecting said valve means and one endof the cylinder to provide for flow of fluid under pressure to thecylinder and for drainage from the cylinder, a second remotely locatedtwo-way acting cylinder and piston device, a second conduit connected tothe other end of the first named cylinder and to one end of said secondnamed cylinder, a third conduit connected to the other end of thesecondnamed cylinder and to the valve means, an implement having an adjustableelement thereon adapted to be flexibly connected to the tractor, saidsecond cylinder and piston device being mounted on said implement andconnected to said adjustable element.

27. A hydraulic power attachment for tractors having a power plantcomprising a pump attached to be driven from the power plant of thetractor, a two-way cylinder, at third conduit connected to the other endof the second named cylinder and to the valve means, and a rockshaftadapted to be mountedon the tractor, the piston of said first namedcylinder and piston device being operably connected to said rockshaft.

28. A hydraulic power attachment for tractors having a power plantcomprising a pump attached to be driven from the power plant of thetractor, a two-way acting cylinder and piston device adapted to bemounted on the tractor, valve means, fluid conducting means connectingsaid pump and said valve means, a conduit connecting said valve meansand one end of the cylinder to provide for flow of fluid under pressureto the cylinder and for drainage from the cylinder, a second remotelylocated two-way acting cylinder and piston device, a second conduitconnected to the other end of the first named cylinder and to one end ofsaid second named cylinder, a third conduit connected to the other endof the second named cylinder and to the valve means, and means forcutting out the remotely located cylinder and for providing acommunication between the second conduit means and the third conduitmeans.

29. A hydraulic power attachment for tractors having a power plantcomprising a pump attached to be driven from the power plant of thetractor, a two-way acting cylinder and piston device adapted to bemounted on the tractor, valve means, fluid conducting means connectingsaid pump and said valve means, a conduit connecting said valve meansand one end of the cylinder to provide for flow of fluid under pressureto the cylinder and for drainage from the cylinder, a second remotelylocated cylinder and piston device, a second conduit connected to theother end of the first named cylinder and to one end of the second namedcylinder, a third conduit connectedto the other end of the second namedcylinder and to the valve means, and means for putting the secondconduit in communication with the third conduit at the end of the strokeof the remote piston whereby the piston in the second named cylinder maybe synchronized with respect to the piston in the first named cylinder.

30. A hydraulic power attachment for tractors having a power plantcomprising a pump attached to be driven from the power plant of thetractor, a two-way acting cylinder and piston device adapted to bemounted on the tractor, valve means, fluid conducting means connectingsaid pump and said valve means, a conduit connecting said valve meansand one end of the cylinder to provide for flow of fluid under pressureto the cylinder and for drainage from the cylinder, at second remotelylocated two-way acting cylinder and piston device, a second conduitconnected to the other end of the first named cylinder and to one end ofthe second named cylinder, a third conduit connected to the other end ofthe second named cylinder and to the valve means, the piston of theremotely located device being provided with valve structure ineludingmeans projecting beyond each side of the piston engageable with the endsof the cylinder to mechanically open said valve structure for the flowof fluid through the piston for synchronization of the pistons when theremote piston reaches the end of its stroke in either direction beforethe piston of the tractor mounted device reaches the end of its strokein the opposite direction.

31. A hydraulic power attachment for tractors having a power plantcomprising a pump adapted to be driven from the power plant, a two-wayacting cylinder and piston device adapted to be mounted on the tractor,valve means, fluid conducting means connecting said pump and said valvemeans, a conduitconnecting said valve means and one end of the cylinder,21 second remotely located cylinder and piston device, a second conduitconnected to the other end of said first named cylinder and to one endof said second named cylinder, 21 third conduit connected to the otherend of said second named cylinder and to the valve means, and means toprovide a communication directly between the second conduit and thethird conduit whereby the tractor mounted cylinder and piston device isoperable independently of the remotely located cylinder and pistondevice, said means for putting the second conduit in communication withthe third conduit including valve means operable by movement of theremote piston at the end of its stroke in either direction toautomatically bring about phasing of the two pistons.

32. A hydraulic power device for tractors having a pump driven by thetractor engine and a reservoir associated therewith and an implementpart movably connected to the tractor and provided with a remoteadjusting piston and cylinder device with conduit connected with thepiston rod end of the cylinder of said device and another conduitconnected with the other end of the cylinder, the combination includingvalve means adapted to be mounted on the tractor, conduit means forconnecting said valve means to the pump and reservoir, a fluiddisplacement device adapted to be mounted on the tractor, said devicehaving a member movable proportionally to and in the direction of fluidflow therein, means for connecting one conduit from the remote cylinderto the valve means, means for connecting the other conduit from theremote cylinder to the fluid displacement device at one side of themovable member, conduit means for connecting the fluid displacementdevice at the other side of the movable member with the valve means, afollow-up control mechanism having one movable member connected to movewith the movable member of the fluid displacement device, a manuallyoperable means to move said member of the follow-up mechanism and meansfor connecting said member to the valve means whereby means are providedfor preselecting any indexed position of the movable member of the fluiddisplacement device on the tractor and by the associated structure tosimultaneously preselect a corresponding position of the piston in theremote cylinder and piston device.

33. A hydraulic power control attachment for tractors having a powerplant with a fluid pump adapted to be driven from the power plantcomprising, a twoway acting cylinder and piston device adapted to bemounted on the tractor, valve means adapted to be mounted on thetractor, fluid conducting means communicating with the valve means andthe pump, fluid conduit means connecting the valve means and one end ofthe tractor mounted cylinder to provide for the flow of fluid to andfrom said cylinder, 4 second remote cylinder and piston device, a secondconduit means connected to the other end of the first named cylinder andto one end of the remote cylinder, a third conduit means connected tothe other end of the remote cylinder and to the valve means, and valvemeans operable with one piston at one end of its stroke in its cylinderfor putting the second conduit in communication with the conduit meansconnected at that end of the cylinder for the flow of fluid with onepiston in fixed position and with movement of the other piston wherebythe phase relationship of the pistons relative to each other may bealtered.

34. A hydraulic power control attachment for tractors having a powerplant, a pump attached to be driven from said power plant, an implementconnected to the tractor,-

a two-way acting hydraulic cylinder and piston device connected to theimplement for adjustment thereof and having a pair of flexible conduitsconnected thereto at opposite sides of the piston comprising valve meansadapted to be mounted on the tractor, fluid conduit means for connectingsaid valve means with said pump, a fluid control device including acylinder and a piston adapted to be monntedvon the tractor, fluidcontrol means connected for delivering fluid from and to said valvemeans and the cylinder at one side of the piston, fluid conduit meansfor removably connecting said valve means to one of the'flexibleconduits of the cylinder and piston device, fluid conduit means forremovably connecting the fluid control device at the other side of thepiston with the other one of the flexible conduits of the cylinder andpiston device whereby said cylinder and piston device may be removed andattached, a closed chamber being provided including the spaces betweenthe pistons and the connected ends of the cylinders, and valve meansproviding for the delivery of fluid to said chamber between the twopistons with one piston in fixed position and with the other pistonbeing displaced whereby the cylinder and piston device may be connectedwith the piston thereof in any phase relationship with respect to thepiston of the flow control device.

35. A hydraulic power attachment for tractors having a power plantcomprising a pump attached to be driven from the power plant of thetractor, a two-way acting cylinder and piston device adapted to bemounted on the tractor, valve means, fluid conducting means connectingsaid pump and said valve means, a conduit connecting said valve meansand one end of the cylinder to provide for flow of fluid under pressureto the cylinder and for drainage from the cylinder, a second remotelylocated two-way acting cylinder and piston device, a second conduitconnected to the other end of the first named cylinder and to one end ofsaid second named cylinder providing thereby a closed chamber includingthe spaces between the pistons at the joined ends of the cylinders, athird conduit connected to the other end of the second named cylinderand to the valve means, said second and third conduits being removableto provide for removing and attaching the second cylinder and pistondevice, an implement having an adjustable element thereon adapted to beflexibly connected to the tractor, said second cylinder and pistondevice being mounted on said implement and connected to said adjustableelement andv means providing for the delivery of fluid to the spacebetween the two pistons with one piston in fixed position and with theother piston being displaced whereby the second cylinder and pistondevice is attachable with the piston therein in any phase relationshipwith respect to the piston of the first cylinder and piston device.

References Cited in the file of this patent or the original patentUNITED STATES PATENTS 1,968,422 Proctor et a1 July 31, 1934 2,072,111Keeler Mar. 2, 1937 2,112,466 Maloon Mar. 29, 1938 2,160,596 Le Bleu May30, 1939 2,276,979 Jacobi Mar. 17, 1942 2,292,961 Mott Aug. 11, 19422,346,857 Meredith Apr. 18, 1944 2,354,274 Orelind July 25, 19442,361,326 Silver Oct. 24, 1944 2,368,125 Evans Jan. 30, 1945 2,368,659Heineck et a1 Feb. 6, 1945 2,386,378 Wippel Oct. 9, 1945 2,409,510. MottOct. 15, 1946 2,410,918 Acton Nov. 12, 1946 2,436,155 Silver Feb. 17,1948 2,485,651 Oerman Oct. 25, 1949

